part ofdevelops_fromcontributes to morphology ofnosenasal septumA median dividing wall, sagittally directed, which divides the nasal cavity into the right and the left nasal fossae. [Dorian_AF, Elsevier's_encyclopaedic_dictionary_of_medicine, Part_B:_Anatomy_(1988)_Amsterdam_etc.:_Elsevier][VHOG]AAO:0000559AAO:0010135EHDAA2:0001234EHDAA2:0004104EHDAA:6809EMAPA:17608FMA:54375GAID:115MA:0000285MESH:A02.165.639Medial vertical wall between nasal capsules.[AAO]Medial, vertical plate that separates the nasal capsules.[AAO]NCIT:C33160OpenCyc:Mx4rv7e-k5wpEbGdrcN5Y29ycAThe nasal septum separates the left and right airways in the nose, dividing the two nostrils. It is depressed by the Depressor septi nasi muscle. [WP,unvetted].UBERON:0001706UMLS:C0027432VHOG:0000017We follow AAO in making this part of the nasal skeletonWhatever the common ancestor of the lamprey and gnathostomes may have looked like, it most likely possessed a neural-crest-derived premandibular ectomesenchyme closely associated with the NHP. Invention of the jaw subsequently required a space for the nasal septum and maxillary process to develop, which might have been provided by subdivision of the NHP into the nasal placode and the hypophysis (diplorhiny, the state of bilaterally separated nasal openings, would also have been a prerequisite for this).[well established][VHOG]septal cartilageseptum mobile nasiseptum nasiseptum of the noseuberonseptumnasal skeletonintermaxillary processneural crest-derived structureethmoid region